NPS Back-Testing

Fred Reichheld published "The One Number You Need to Grow" in *Harvard Business Review* in 2003, formally introducing NPS (Net Promoter Score). He replaced dozens of pages of satisfaction surveys with a single question: "How likely are you to recommend this company to a friend?" On a 0-10 scale, 9-10 are promoters, 0-6 are detractors. Promoter percentage minus detractor percentage equals the NPS.

Reichheld subsequently partnered with Bain & Company to track 200 companies over three years. For every 10-point increase in NPS, revenue growth rate averaged 2.5 percentage points above industry peers.

But the point isn't the score itself — it's the structured analysis of "promoters' reasons for recommending" and "detractors' reasons for criticizing." That's exactly what this resort did: instead of asking "what's the score," they asked "why promote, why not promote," and then acted on the root causes.

Reichheld later added a key insight in his 2020 book *Winning on Purpose*: high NPS isn't achieved by "making everyone happy." It's achieved by "first solving detractors' pain points, turning them into at least neutral." Because the negative word-of-mouth generated by one detractor is 2-3 times more powerful than the positive word-of-mouth from one promoter. Eliminating detractors is more efficient than creating promoters.